[Interest] Sporadic crash in QtWayland v5.9.5 on killing a window

Sunder Negi ssnsundersinghnegi at gmail.com
Tue Jul 17 06:54:38 CEST 2018


I am using QtWayland v5.9.5 with wayland v1.11.1 and Vivante driver

I am finding below crash sporadically on window close.

#0  get_next_argument (signature=0x0,
details=details at entry=0x6b6edd60) at
#1  0x73b8e734 in wl_argument_from_va_list (signature=<optimized out>,
args=<optimized out>, count=20, ap=...) at
#2  0x73b8c908 in wl_proxy_marshal_constructor (proxy=0x46b1a8,
opcode=opcode at entry=3, interface=0x73ba1714 <wl_callback_interface>)
at /usr/src/debug/wayland/1.11.1-r3.2/wayland-1.11.1/src/wayland-client.c:817
#3  0x755eb56c in wl_surface_frame (wl_surface=<optimized out>) at
#4  gcoOS_SetDisplayVirtualEx (Display=<optimized out>,
Window=0x66cd9bac, Context=0x66cd9cc4, Surface=<optimized out>,
Offset=0, X=0, Y=0) at gc_hal_user_wayland.c:1691
#5  0x7551c44c in veglSetDisplayFlip (Display=Display at entry=0x3db3c,
Surface=<optimized out>, BackBuffer=BackBuffer at entry=0x66cda428) at
#6  0x75516d0c in veglSwapWorker (Display=0x3db3c) at gc_egl_swap.c:741
#7  0x75ae7f5c in start_thread (arg=0x6b6ee450) at
#8  0x75ddd408 in ?? () at ../sysdeps/unix/sysv/linux/arm/clone.S:86
from /lib/libc.so.6

Suspecting heavy CPU load i tried to simulate the issue. I made a
client and added the following to its kill function

    // delay destruction until we hit another render sync
    QTimer::singleShot(10, this, [=]{
        if (windows.isEmpty()) {
          qDebug() << "no window, aborting";

My query is whether this way of simulating the delayed window closure
correct? I mean would this above code often lead to crash?

Complete code is at

Sunder Singh Negi

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